System and Method for Testing of Micro-Sized Materials

ABSTRACT

Apparatus and methods for testing sediment submerged in liquid and manufacturing the apparatus.

CROSS-REFERENCE

This Application is a continuation of and claims the benefit of priorityunder 35 U.S.C. §120 based on U.S. Non-Provisional patent applicationSer. No. 13/616,163 filed on Sep. 14, 2012, which is a non-provisionalapplication claiming priority to Provisional U.S. Patent Application No.61/592,276 filed on Jan. 30, 2012, under 35 USC 119(e), both of whichare incorporated by reference into the present disclosure in theirentirety.

BACKGROUND

The embodiments disclosed herein relate generally to compression ortension testing of flocculated sediments, an aggregate mixture of clayminerals and biopolymers, referred to herein alternatively as “floc” or“sediment”. To test a floc, it should remain saturated and submerged inthe formation solution. The floc must be easily isolated from otherflocs for single floc geotechnical compression tests that can be maderelatively rapidly on a large number of samples. A device to test a flocshould have minimal and quantifiable frictional resistance to motion,minimal and quantifiable cantilever effect, and minimal, known, orquantifiable compressional resistance of the manipulator tips.Fine-grained sediment transport, deposition and consolidation of softsediments is determined, in part, by a complex relationship betweensediment makeup and geotechnical properties of clay-aggregates.Compression tests on soft sediment grains that are comprised of clay andpolymers can help to better understand how contact interactions couldalter the aggregate properties and influence sediment processes oftransport, deposition, and consolidation in estuarine and nearshorelittoral environments. Compression tests can provide data that can beincorporated into numerical models, which can be used to predictsediment transport processes. In order to determine the compressivestrength of clay aggregates, a highly sensitive load cell and mechanismto hold the small specimens (˜0.5 to 2 mm in diameter) in a controlledvertical plane are needed. Such a device would require a fluidreceptacle within which the specimen is submerged and resting on asample plate. The sample plate could be manipulated upward, via astepper motor-driven lift that could push the specimen at a controlledand specified rate into the “punch” that could be connected to a loadcell. The load cell could transfer the information to a computer thatcould quantify the force required to deform the specimen. Such a devicecould be used in nano/micro mechanical testing of individual flocs, orother small particles, in sizes that range from approximately 10 toapproximately 5000 microns. The device could facilitate compressiontests of flocs that are comprised of clay and polymers mixed in fresh orsalt water for which the pH, or other chemistry, varies. The devicecould also facilitate imaging the deformation process in real-time, andcould use that capability to correlate the floc compressive deformationprocess by generating a graphical representation of a force-displacement(i.e., compression) curve. The compression data could then be readilyused to address the influence of contact interactions between flocs anddeformation of those flocs in discrete element models of sedimenttransport.

What is needed is an environmental cell for nano/micro mechanical andbiomechanical testing to facilitate compression or tension tests of softsediment aggregates that include clay and polymers mixed in fresh andsalt water and which are retained in a liquid of the same salinity,alternatively for testing biological materials such as, for example,blood cells, virus, and bacteria, and also gels, foams, rubbers, surfacecoatings, and food. Currently, compression tests are not conducted onsmall aggregates that are comprised of soft, low-strength, materials.Also, there are no technologies available that can quantify the Young'smodulus of these grains. Currently, these measurements are not made onsoft, low-strength, materials.

SUMMARY

This system and method of the present embodiment can enable testing ofsimilar specimens in aqueous environments, such as food materials,cosmetics, chemicals, etc. The apparatus and methods of the presentembodiment can provide for nano/micro mechanical testing of micro-sizedmaterials submerged in liquid, facilitating specimen preparation andinstallation, and can provide hydrated materials. The apparatus caninclude cell walls with optical magnifying lenses so that themicro-sized specimens can be viewed without the aid of a microscope. Forexample, compression or tension tests of soft sediment aggregates andbiological materials can be performed. The apparatus may have nofrictional resistance between the parts that move to compress the flocs.The water bath can be maintained at a specific elevation and, becausethe water level or “the buoyant force” can be sensed by the load cellon, for example, but not limited to, an AGILENT TECHNOLOGIES® T150 NanoUTM. The UTM, or other similar device, includes, but is not limited toincluding, a frame that holds a load cell, a base plate, and a steppermotor that can move the base plate towards the load cell, and a computerthat can transfer data from the load cell to a storage medium,reproducible and discernible results can be achieved. The 10× magnifierscan locate flocs and position them between the “compression punch” and“sample holder”. The clear imaging window can enable photography andmovies of the floc during the compression test. A single floc or othermaterial can be submerged in fluids of varied ionic strength and pH. Atleast two 10×, for example, viewing windows can be positioned atpreselected angles to facilitate sample loading and alignment of smallparticles. The apparatus can enable real-time movies of compressiontests to be captured. The apparatus can enable testing of compression inaqueous systems with, for example, but not limited to, an AGILENTTECHNOLOGIES® NanoUniversal Loading Frame and similar devices from othercompanies. The apparatus can be used to determine the fate andsurvivability of river-borne aggregates in estuarine and littoral zonewaters. Further, the device can be used to quantify Young's moduli ofsmall granular materials. The data produced by the device can be used tomake predictions of grain interactions associated with sedimenttransport, specifically sediment transport of fine-grained sedimentaggregates. The data may also be used to address the strength ofsimilarly sized composite materials with low strength, such as beads,elastomers, food products, and cosmetics.

An environmental cell can be manufactured for nano/micro mechanicaltesting of micro-sized materials submerged in liquid, facilitatingspecimen preparation and installation, and providing hydrated materials.For example, compression or tension tests of soft sediment aggregatesand biological materials can be performed. The apparatus can determinethe compressive strength, elastic moduli or Young's moduli, of soft,sediment aggregates comprised of clay or clay and biopolymers. Theapparatus can further collect data on clay aggregates as well as foodmaterial (for example, but not limited to, tofu and gelatin) which hassimilar compressive strength.

The environmental cell can be coupled to a load cell (for example, butnot limited to, Agilent UTM-150 with 50 nN force resolution). The loadcell can be contained in a frame, inverted in the present embodiment,and can have a stepper motor. The environmental cell can be placed on astage that is connected to the stepper motor, the stage also beingconnected to the environmental cell, the environmental cell containingthe fluid and the sediment aggregate. The sediment aggregate is thenpositioned to contact the punch pin that is connected to the load cell,so that as the load cell is moved upward at a computer controlled rate(the strain rate), the load cell can detect the force of the sedimentaggregate during displacement of the environmental cell. During thistime period, a video camera collects images of the sediment aggregate,stills that can be used to produce a video. The displacement of theenvironmental cell is time-synched with the force determination and thenthis information is plotted as a force curve (force vs. displacement) inreal-time on the load cell computer.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic diagram of the apparatus of the presentembodiment;

FIG. 2 is a CAD-drawing of the apparatus of the present embodiment;

FIG. 3 is a virtual photographic representation of the apparatus of thepresent embodiment;

FIG. 4 is a photographic representation of the apparatus of the presentembodiment as it would be coupled to the load cell device and positionedwith respect to the image capture system;

FIG. 5 is a photographic representation of the apparatus of the presentembodiment as it would be coupled to the load cell device and positionedwith respect to the image capture system with indication that thecompression test data and the images are transferred to differentcomputers;

FIG. 6 is a photographic representation of the flocs under compressionduring various phases of the displacement during the compression test;

FIG. 7 is a graphical depiction of compressive strength of clay/organicmatter mix that relates the images of FIG. 6 to locations on the graph;

FIG. 8A is a flowchart of the method for assembling the apparatus of thepresent embodiment;

FIG. 8B is a flowchart of the method of collecting compression datausing the apparatus of the present embodiment; and

FIG. 8C is a flowchart of the method of testing sediment data using theapparatus of the present embodiment.

DETAILED DESCRIPTION

The problems set forth above as well as further and other problems aresolved by the present teachings. These solutions and other advantagesare achieved by the various embodiments of the teachings describedherein below.

Referring now to FIG. 1, apparatus 100, viewed from top view 130 andside view 140, can include, but is not limited to including, base plate101 made from, for example, DELRIN®, imaging window plate 103 made from,for example, acrylic, side plates made from, for example, acrylic,magnifying window magnifying lens 107 made of, for example, but notlimited to, glass, sample holder 109 made from, for example, stainlesssteel, O-rings 113 made from, for example, butyl nitrile rubber, andcompression punch 111 made from, for example, stainless steel. Fluidbath 115 can hold enough supernatant fluid to maintain the constantchemistry of the hydrated materials during the test. Apparatus 100 canprovide a means to hold, locate, and maintain properties of aggregateduring compression tests of soft materials in an aqueous environment,and can automatically compute a force-displacement curve. This canenable tests of compressive strength while enabling the operator to viewthe placement of the floc and deformation of the floc through magnifiedlenses 107 and to capture images of the deformation process with amicroscope through picture imaging window 103. The determination of theelastic moduli, among other material properties, can be computed basedon the force-displacement curve and the particle size information.

Apparatus 100 can allow fluid to be maintained with the sample, whichcan be emplaced on a surface mounting rod, also referred to herein assample support rod, 109 and viewed through 10× magnifying windows 103,which can render apparatus 100 suitable for viewing micrometer-sizedobjects. The sample material can then be compressed under a controlledload and viewed with a microscope at high resolution/magnification so asto capture information on strain and deformation. Apparatus 100 can becoupled with, for example, but not limited to, a device to performnanomechanical testing, for example, AGILENT TECHNOLOGIES® UTM T150,which can be used to measure compressive strength and therefore extendthe capabilities from simple tensile strength tests.

Referring now to FIG. 2, environmental cell 102 of apparatus 100(FIG. 1) can include blank side plates 137 and lens side plates 135 madeof, for example, but not limited to, acrylic, that are connected to eachother, for example, but not limited to, by gluing using, for example,but not limited to, acrylic solvent. Lens side plates 135 can be madeof, for example, but not limited to, acrylic which can measure, but isnot limited to measuring, approximately two inches in height,approximately 2.46 inches in width, and approximately 0.23 inches inwidth. Lens side plates 135 can include magnifying lens 107, forexample, but not limited to, 10× magnifying lenses, made out of, forexample, but not limited to, glass, which can be fixed in place, forexample glued, using, for example, but not limited to, 3M® 5200 adhesivesealant. Lens side plates 135 can also include lens recesses 139. canalso include base plate 101 such as, for example, but not limited to, aDELRIN® plate glued to blank side plates 137 and lens side plates 135using, for example, but not limited to, 3M® 5200 adhesive sealant. canalso include for example, but not limited to, No. 2006 O-rings 113, andsample support rod 109 made from, for example, but not limited to, 316stainless steel. The configuration and sizes of blank side plates 137and lens side plates 135 can be different from the depicted embodiment.

Referring now to FIG. 3, environmental cell 102 is shown in useincluding fluid bath 115. Lens side plates 135, 10× magnifying windows107, DELRIN® base plate 101, and sample support rod 109 are also shown.

Referring now to FIG. 4, embodiment 104 of environmental cell 102(FIG. 1) is shown from two points of view. Embodiment 104 can includevideo camera 201 that is attached to microscope 215 and load cell device203 in an inverted position, compression punch 111, flags 206 tomaintain load cell in parked position, load cell 207, clay floc 209,stage manipulators 211, magnifying view windows 213 to facilitate sampleloading, orienting, and aligning with respect to compression punch 111,by reorienting micromanipulator stage 217 with stage manipulators 211 tomove environmental cell 102 that is connected to stage mount 219, andbelt-drive 221 that can migrate stepper motor plate 212 andmicromanipulator stage 217 upwards. During this process, as belt-drive221 moves stepper motor plate 212, micromanipulator stage 217, andenvironmental cell 102 upwards, pre-aligned floc 209 can interact withcompression punch 111 and load cell 203 to transfer force anddisplacement data to a load cell computer (not shown). Simultaneously,video camera 201 can capture imagery of the floc 209 deformation and cantransport the images to an image processing computer (not shown).

Referring now to FIG. 5, video camera 201 having connecting cables 245,connecting video camera to image processing computer (not shown) isshown with respect to the load cell device 203, for example, but notlimited to, AGILENT TECHNOLOGIES® UTM150, and principal components ofload cell 207, compression punch 111, environmental cell 102,micromanipulator stage 217, stage manipulators 211, stepper motor plate212, and belt-drive 221 that can migrate micromanipulator stage 217 andenvironmental cell 102 upwards. Load cell 203 can collect data that aretransferred to the data processing load cell computer (not shown); videocamera 201 can transfer data to an image processing computer (notshown).

Referring now primarily to FIG. 6, compression/deformation of floc 209is shown in a series of images ((a)-(h)) that capture the verticalmigration of environmental cell 102 (FIG. 3) as sample support rod 109(FIG. 3) drives floc 209 into compression punch 111. These imagescorrespond to FIG. 7, the graph of load versus compression. During thisprocess, floc 209 is submerged in the supernatant fluid within theenvironmental cell 102, which can migrate upward to push floc 209 (andsample support rod 109) through supernatant fluid 115 and, eventually,into contact with floc 209 to the end of the test where environmentalcell 102 (FIG. 3) and sample support rod 109 (FIG. 3) can reversemigration to unload floc 209, which remains deformed (image (h) in FIG.6).

Referring now to FIG. 7, graph 281 of load versus compression is shownfor the compression of gray-green aggregate made of clay, e.g. illite,and organic matter, e.g. guar, mixed in salt-water of neutral pH. Thegraph shows the load in mN and compressive displacement of the loadcell. Letters displayed along curve 283 correspond to images (a)-(h) inFIG. 6.

Referring now primarily to FIG. 8A, method 150 for assemblingenvironmental cell 102 (FIG. 2) can include, but is not limited toincluding, the steps of preparing two magnifying walls 135, imagingwindow 103, and side wall 137, machining 151 compression punch 111 (FIG.1), cutting 153 sample support rod 109 (FIG. 1) to radial and lengthdimensions and cutting threads inside sample support rod 109 (FIG. 1)and o-ring grooves 113 (FIG. 1) outside, cutting 155 a magnifyingwindow, to mount magnifying lens 107 (FIG. 1), and recesses inmagnifying walls 135 (FIG. 3), cutting 157 base plate 101 (FIG. 1) anddrilling a hole in base plate 101 (FIG. 1) to accommodate sample supportrod 109 (FIG. 1), gluing 159 base plate 101 (FIG. 1) to each of imagingwindow 103 (FIG. 3), magnifying walls 135 (FIG. 3), and side wall 137(FIG. 3) to form a water bath area, attaching 161 o-rings 113 (FIG. 1)to the sample support rod 109 (FIG. 1), attaching 163 sample support rod109 (FIG. 1) to a threaded attachment on a stage manipulator.

Referring now to FIG. 8B, method 250 for collecting compression data ona floc 209 (FIG. 1) can include, but is not limited to including, thesteps of attaching 251 threads of sample support rod 109 (FIG. 1) to athreaded rod on a sample stage, sample support rod 109 (FIG. 1) beingpositioned within environmental cell 102 (FIG. 2), filling 253environmental cell 102 (FIG. 2) with a preselected volume of saturatingfluid, installing 255 samples flocs 209 (FIG. 1) to be evaluated onsample support rod 109 (FIG. 1), if in manual mode, freeing 257compression punch/load cell 111 (FIG. 1) for movement from its flaggedposition, if in computer-controlled mode, migrating 259 theenvironmental cell towards compression punch 111 (FIG. 1), aligning 261compression punch 111 (FIG. 1) with sample floc 209 (FIG. 1) to beevaluated by rotating knobs on the sample stage using magnifying lens107 (FIG. 1) associated with environmental cell 102 (FIG. 1) to assistviewing the alignment, and executing 263 a rate/load dependent computercompression test.

Referring primarily to FIG. 8C, method 350 (FIG. 8C) for testingsediment can include, but is not limited to including, the step ofinserting 351 (FIG. 8C) compression punch 111 (FIG. 4) into load cell207 (FIG. 4), while load cell 207 (FIG. 4) is in the a parked position,for example, when flags 206 (FIG. 4) are inserted into load cell 207(FIG. 4). Method 350 (FIG. 8C) for testing sediment can further includethe steps of attaching 353 (FIG. 8C) environmental cell 102 (FIG. 4) tostage mount 219 (FIG. 4) resting atop micromanipulator stage 217 (FIG.4) that is attached to stepper motor plate 212 (FIG. 4), loading 355(FIG. 8C) environmental cell 102 (FIG. 4) with the water from which thesediment is obtained, positioning 357 (FIG. 8C) the sediment on baseplate 101 (FIG. 1), and positioning 359 (FIG. 8C) the sediment belowcompression punch 111 (FIG. 4) by adjusting stepper motor plate. Method350 (FIG. 8C) can still further include the steps of moving 361 (FIG.8C) the stepper motor plate towards compression punch 111 (FIG. 44),computing 363 (FIG. 8C) a strain rate based on step 361 (FIG. 8C),measuring 365 (FIG. 8C) the sediment resistance of the sediment based onthe strain rate and the stepper motor plate displacement, and recording367 (FIG. 8C) the sediment resistance and the stepper motor platedisplacement on a computer-readable medium. Method 350 (FIG. 8C) canoptionally include the steps of collecting images of the sediment duringthe step of moving 361 (FIG. 8C) the stepper motor plate towardscompression punch 111 (FIG. 4), and computing any of the compressionstrength, the Young's modulus, and the elastic modulus of the sedimentaggregate based on the sediment resistance and the images. Method 350(FIG. 8C) can further optionally include the steps of adjusting thestepper motor plate by micromanipulators, and collecting the imagesthrough lens side plate 135 (FIG. 3) of environmental cell 102 (FIG. 4).Method 350 (FIG. 8C) can still further optionally include the steps ofobtaining the sediment from any of a river, a laboratory, and an oceanbottom, and positioning the sediment on base plate 101 (FIG. 4) using apipette. Method 350 (FIG. 8C) can even further optionally include thesteps of situating magnifying lenses 107 (FIG. 4) at 90° angles to eachother, aligning the magnifying lenses until the sediment is in line withcompression pin 111 (FIG. 4), and verifying the alignment based on theimages.

Referring again primarily to FIGS. 8A and 8B, methods 150 (FIG. 8A) and250 (FIG. 8B) can be, in whole or in part, implemented electronically.Signals representing actions taken by elements of apparatus 100 (FIG. 1)and other disclosed embodiments can travel over at least one livecommunications network (connected by communication cables 247 (FIG. 5)).Control and data information can be electronically executed and storedon at least one computer-readable medium accessible by cables 247 (FIG.5). Apparatus 100 (FIG. 1) can be implemented to communicate with atleast one computer node in at least one live communications network.Common forms of at least one computer-readable medium can include, forexample, but not be limited to, a floppy disk, a flexible disk, a harddisk, magnetic tape, or any other magnetic medium, a compact disk readonly memory or any other optical medium, punched cards, paper tape, orany other physical medium with patterns of holes, a random accessmemory, a programmable read only memory, and erasable programmable readonly memory (EPROM), a Flash EPROM, or any other memory chip orcartridge, or any other medium from which a computer can read. Further,the at least one computer readable medium can contain graphs in any formincluding, but not limited to, Graphic Interchange Format (GIF), JointPhotographic Experts Group (JPEG), Portable Network Graphics (PNG),Scalable Vector Graphics (SVG), and Tagged Image File Format (TIFF).

Although the present teachings have been described with respect tovarious embodiments, it should be realized these teachings are alsocapable of a wide variety of further and other embodiments.

What is claimed is:
 1. A apparatus for characterizing mechanicalproperties of a sample, comprising: a container configured with at leastone magnifying port and at least one opening, the container holding apre-selected depth of fluid; a sample support rod extending from a wallof the container, the sample support rod being configured to hold thesample so that it is submerged in the fluid and positioned based on amagnifying device situated in the at least one magnifying port, thesample support rod being further configured with a mechanical driveforcing the container; and a compression punch being positioned at oneof the at least one the openings, the compression punch configured witha load cell; wherein the sample support rod and the sample interact withthe compression punch to generate force and displacement datacharacterizing the mechanical properties of the sample, the force anddisplacement data being automatically transferred to a load cellcomputer by the load cell, the load cell computer automaticallytranslating the force and displacement data into a force-displacementcurve indicative of the material properties of the sample.
 2. Theapparatus according to claim 1, wherein the at least one openingcomprises a port for manipulating the sample.
 3. The apparatus accordingto claim 1, wherein the magnifying device comprises a permanentlyintegrated magnifying lens.
 4. The apparatus according to claim 1,wherein the magnifying device comprises a temporarily integratedmagnifying lens.
 5. The apparatus according to claim 1, wherein themagnifying port comprises a camera attachment.
 6. The apparatusaccording to claim 1, wherein the magnifying device comprises amagnifying lens and a camera.